1. Field of the Invention
This invention relates to rotary-actuators in the form of door-knobs, and more specifically it relates to doorknobs and associated latches for hinged-doors employing anti-ligative ensnaring resistant means, hence particularly suited to institutional usage (i.e. psychiatric-institutions, hospitals, jails, etc.)—as an impulsive-suicide deterrent.
2. Relevant Prior Art
Presently there are several door-lock companies producing what they elude to as anti-ligative suicide deterrent door-knobs, nevertheless successful attempts continue to be achieved via these hardware owing their for one reason or another still not achieving true non-ensnarable construction. For example, some firms produce door-knobs which while perhaps designed free of ensnarable declivities, such as eliminating the traditional bulbuls grasping-knob,—yet employ to shallow a pitch or slope of the doorknob,—thereby unwittingly enabling a person to snag a loop of cord there around, and ultimately obtain some manner of cross-lashing to the opposite like designed door-knob for example. Still other manufacturers make L-shaped door-knobs claimed to be anti-ligative, which are nevertheless predictably ensnarable no matter how slick their design,—merely by means of crosslashing. However, I have discovered and make full disclosure herein, of a critical transition-point technique of construction to which no cording can be successfully secured;—this vitally critical slope or pitch angle being an approximate minimum of 40-degrees (—as measured relative to the door-knob's central-axis of rotation).
Background research discovery provided relatively little prior patent-art regarded as germane to this disclosure, chronologically for example U.S. Pat. No. 3,792,877 (filed: June 1972) shows a latch-bolt member (102) of cylindrical design, which poses a typical problem with regard to the nature of its horizontal slide-surface providing a potential ensnaring point where a small cord such as a shoelace or electrical-cord could be lodged in an ensnaring manner by a mentally-depressed person impulsively intent upon terminating themself via a contrived hanging-noose means.
In U.S. Patent Application Publication No. 2003/0135956 (filed: January 2003) is shown an ergonomic “ErgoHandle,” which exhibits a novel snare preventative configuration,—however it is entirely remiss of any positive-acting latching and release means;—therefore as such, it is essentially limited for usage in conjunction with cabinet-doors and drawers and the like.
In U.S. Patent Application Publication No. 2006/0220398 (filed: March 2006) shows an doorknob which in its FIGS. 1 & 2 embodiment is substantially free of surface undulations such as a reduced neck-diameter which would enable a person to snag a cord like entity such as a shoelace; —however, the joint-crevice created where the doorknob (1) merges with the decorative-ring (2), along with the overall shape of the doorknob projecting at a right-angle from the door-surface, in of itself constitutes a convenient ensnarable protrusion. Accordingly, while ergonomic in design relative to the inventor's desire to provide a doorknob offering improved rotational grasping ability, the substantially cylindrical shape still poses the inherent problem of ensnarability residing in all conventional doorknobs.
Additionally, there is a less germane class of utility-knobs such as have been designed for gas-burner valve-controls for kitchen-stoves, and radio control-knobs, such as are generally exemplified in U.S. Pat. No. D114,315 (filed: October 1938) showing a 3-finned knob, No. D145,210 (filed: November 1945) showing a 4-finned knob, and No. D267,194 (filed: January 1980) showing a 6-finned;—however, none of the designs anticipated an anti-ligative purpose, whilst all of the designs employed shapes which characterized exactly the problem which my invention serves to overcome, whereby each of them would allow a cord to be lodged transversely across their finger-hold fins without sliding off;—while also posing the potential to secure a cord of some sort behind the base of the knob.
Therefore, in full consideration of the preceding patent review, there is revealed a need for an improved form of hardware to which these identified prior-art inventions have been at least remotely addressed. The inventor hereof believes their newly improved door-knob device, referred commercially to as the LIFESTAR™ doorknob, being developed for production under auspices of Shilts-Mfg./Mkt. Co., exhibits certain unique human-factors design advantages, as shall become clearly revealed in the subsequent portion of this disclosure.